The demand for new and improved electronic and electro-mechanical systems has placed increased pressure on the manufacturers of energy storage devices to develop battery technologies that provide for high energy generation in a low-volume package. A number of advanced battery technologies have recently been developed, such as metal hydride (e.g., Ni--MH), lithium-ion, and lithium polymer cell technologies, which would appear to provide the requisite level of energy production and safety margins for many commercial and consumer applications.
Such advanced energy storage systems, however, typically produce a significant amount of heat which, if not properly dissipated, can result in a thermal runaway condition and eventual destruction of the energy storage device, as well as the system being powered by the energy storage device. A conventional approach of providing a heat transfer mechanism external to a high-energy electrochemical cell or grouping of cells, for example, may be inadequate to effectively dissipate heat from internal portions of the cells. The severity of consequences resulting from short-circuit and thermal run-away conditions increases significantly as system voltage and current demands increase.
Other characteristics of advanced battery technologies provide additional challenges for the designers of advanced energy storage devices. For example, certain advanced cell structures are subject to cyclical changes in volume as a consequence of variations in the state of charge of the cell. Such repetitive changes in the physical size of a cell significantly complicates the electrical interconnection strategy and thermal/mechanical housing considerations.
There is a need in the advanced battery manufacturing industry for a methodology by which high-energy, highly exothermic electrochemical cells can be safely packaged for use in a wide range of applications. There exists a further need for a thermal management apparatus which accommodates the unique dynamics of an electrochemical cell which is subject to volumetric changes during charge and discharge cycling. The present invention fulfills these and other needs.